Motor vehicle comprising at least two drive motors and an automatic transmission with fixed transmission ratio steps and a power-split transmission ratio step

Abstract

The present invention relates to a motor vehicle having at least two drive motors, at least one of which is an electric motor, and a high-voltage accumulator and an automatic transmission having at least one fixed transmission ratio step and at least one power-split transmission ratio step for adjusting the transmission ratio starting from the at least one fixed transmission ratio step. The motor vehicle according to the present invention also has an electronic control unit that includes a speed control module that can be activated during a transmission ratio change. The speed control module is designed to precalculate a target speed, by which both a speed gradient and a speed curvature can be limited, wherein a target speed of the at least one drive motor is continuously compared with a maximum permissible speed gradient and a maximum permissible speed curvature.

Description

Technical Field

[0001] The invention relates to a motor vehicle having at least two drive motors, at least one of which is an electric motor, the motor vehicle having a high-voltage accumulator, an automatic transmission having at least one fixed transmission ratio step and at least one power-split transmission ratio step for adjusting the transmission ratio starting from the at least one fixed transmission ratio step, and an electronic control unit. Background Art

[0002] Automatic transmissions for motor vehicles are known. Furthermore, automatic transmissions for hybrid electric vehicles are known, which, in addition to an internal combustion engine, also have at least one electric motor for propulsion. Current automatic transmissions for hybrid electric vehicles (hybrid transmissions) are often based on existing automatic transmissions. The electric motor for electrification is often positioned between the internal combustion engine and the transmission (a so-called P2 hybrid). However, this hybridization does not offer advantages for the transmission itself.

[0003] Transmissions suitable for hybridization are, for example, power-shift automatic transmissions, which offer different fixed gear ratio steps via friction-locked shifting elements. In such transmissions, at least one shifting element operates in a slipping state during gear changes. The friction work generated during slipping is converted into heat, which must be removed from the friction-locked shifting element via a sufficient flow of cooling oil. Furthermore, friction-locked shifting elements generate corresponding drag losses in the open state. The shifting elements are typically hydraulically controlled. To enable them to transmit force in the closed state, the friction plates of the shifting elements must be continuously pressed against each other with a correspondingly high hydraulic pressure. The hydraulic pump required for this is used not only for cooling but also for operating the shifting elements. However, the hydraulic pump requires a certain amount of power to operate, which reduces overall efficiency.

[0004] According to the technical solution of DE 10 2017 217 133 A1, an automatic transmission is provided, which comprises an internal combustion engine, at least two fixed transmission ratio stages, three transmission shafts, an epicyclic gear train, two shifting elements, and a variator. The first side of the variator can be coupled to the first transmission shaft for torque transmission, and the second side of the variator can be coupled to the epicyclic gear train via the second transmission shaft for gear ratio adjustment. This means that the second side of the variator, together with the internal combustion engine and the output of the automatic transmission, operates in a three-shaft manner. Thus, the second side of the variator has a gear ratio adjustment effect on the internal combustion engine via the epicyclic gear train. The variator enables continuous gear ratio adjustment. Therefore, other gear ratios, in particular, any intermediate states between the fixed gear ratio stages, can be adjusted independently of the fixed gear ratio stages. The variator preferably comprises two electric motors, one of which operates as a generator and the other as a motor. By temporarily converting mechanical energy into electrical energy, the speeds of the two electric motors can be decoupled, thus providing the variator function. The epicyclic gear train transmission mechanism may be a planetary gear transmission mechanism. Summary of the Invention

[0005] The object of the present invention is to improve a hybrid motor vehicle of the type mentioned at the outset with an automatic transmission with regard to the transmission ratio adjustment.

[0006] The present invention relates to a motor vehicle having at least two drive motors, at least one of which is an electric motor, and comprising a high-voltage accumulator and an automatic transmission having at least one fixed transmission ratio step (fixed gear) and at least one power-split transmission ratio step (E-CVT) for adjusting the transmission ratio starting from the at least one fixed transmission ratio step. For example, leaving a single fixed gear and entering the power-split transmission ratio step (E-CVT) is also important.

[0007] The present invention relates in particular to a motor vehicle having an internal combustion engine, at least one electric motor, and an automatic transmission having at least two fixed transmission ratio steps and a transmission mechanism for adjusting the transmission ratio between the two fixed transmission ratio steps, wherein the transmission mechanism comprises, for example, two electric motors. Alternatively, a single electric motor may suffice. In this case, the transmission mechanism comprises the electric motors and a high-voltage accumulator.

[0008] The motor vehicle according to the present invention further comprises an electronic control unit having a speed control module that can be activated during a transmission ratio change. The speed control module is designed to precalculate a target speed, by which both the speed gradient and the speed curvature can be limited, wherein a target speed of the at least one drive motor is continuously compared with a maximum permissible speed gradient and a maximum permissible speed curvature.

[0009] The present invention has, for example, a transmission mechanism formed by two electric motors. During the transmission ratio change, the first electric motor operates as a generator and the second electric motor operates as a motor. However, the first electric motor can also operate as a motor before the transmission ratio is adjusted.

[0010] The shift element is preferably a positive-locking shift element (e.g., a claw). This has the advantage that the shift element can be held or locked in the closed position with low force. This reduces the energy consumption for maintaining a fixed transmission ratio step, thus increasing overall efficiency. Furthermore, in the open state of the positive-locking shift element, (almost) no drag losses occur.

[0011] According to another advantageous embodiment of the present invention, a first shifting element is provided for engaging a first fixed transmission ratio step, and a second shifting element is provided for engaging a second fixed transmission ratio step. This means that each fixed transmission ratio step is assigned a preferably separate shifting element, by means of which the transmission ratio step is engaged and, in particular, held closed. Alternatively, multiple shifting elements may be provided for engaging a single fixed transmission ratio step, and / or separate shifting elements may be provided for engaging multiple fixed transmission ratio steps.

[0012] In this way, the transmission can be switched between two fixed transmission ratios using a continuously adjustable transmission ratio (E-CVT) while maintaining tractive force. Power flows through the transmission only during the shift between fixed transmission ratios, which is generally less efficient than purely mechanical power transmission. In particular, no power flows through the transmission when a fixed transmission ratio is engaged. By providing power transmission for the fixed transmission ratios through appropriate shift elements, the automatic transmission can achieve high efficiency.

[0013] In the shifting method according to the invention, the first electric machine of the transmission can be coupled at least temporarily to the transmission shaft in a torque-transmitting manner in order to input torque into the transmission or to extract torque therefrom.

[0014] Furthermore, the second electric machine of the transmission can be coupled at least temporarily to the epicyclic gear train via a shaft in a transmission ratio-adjustable manner. This means that the second side of the transmission has a transmission ratio-adjusting effect on the internal combustion engine via the epicyclic gear train, in particular by virtue of the second side of the transmission being in three-shaft operation together with the internal combustion engine and the output of the automatic transmission.

[0015] In principle, reference is also made to DE 10 2017 217 133 A1 for explaining the transmission design.

[0016] Essential to the invention according to the present application is therefore a speed control module which is designed to precalculate a setpoint speed by which both the speed gradient and the speed curvature can be limited, wherein the target speed of the at least one drive motor is continuously compared with a maximum permissible speed gradient and a maximum permissible speed curvature.

[0017] The present invention is based on the following considerations:

[0018] In contrast to conventional speed control tasks of the drive motors, in power split operation, i.e., in a motor vehicle having at least two drive motors, at least one of which is an electric motor, and an automatic transmission having at least one fixed transmission ratio step and at least one power split transmission ratio step for transmission ratio control, the transmission output torques of the two drive motors, in particular the internal combustion engine and the electric motor, must be adjusted in parallel with the speed control task in accordance with the driver's request (e.g., communicated via the accelerator pedal position).

[0019] For this purpose, form-locking shift elements are used, which allow only a very small speed window to engage a fixed gear (i.e. a fixed transmission ratio step) from a power-split gear (i.e. a power-split transmission ratio step) without damage and imperceptibly for the driver.

[0020] In the prior art, friction-locking or combined friction-locking shift elements have been used so far, which can even assist in synchronizing the desired gear at large speed differences. This is achieved by a low level of friction torque, which is imperceptible to the driver but has a stabilizing effect on the speed control task.

[0021] To use form-locking shifting elements, the speed control task must be performed solely by the internal combustion engine and the electric motor in power-split operation. The internal combustion engine has a significant disadvantage compared to the electric motor: it can adjust its torque with widely varying torque gradients depending on its possible operating point. However, the maximum possible adjustable torque gradient is crucial for the dynamics of the speed control task, i.e., the duration of the adjustment of the internal combustion engine speed between two transmission ratio steps.

[0022] Therefore, in order to utilize the full dynamics of the electric motor and the internal combustion engine during speed regulation in power split operation, it is necessary to precalculate the desired speed profile (setpoint speed) of the internal combustion engine and the electric motor over time. Conventional speed gradient limiting is not sufficient for this purpose, as the internal combustion engine and the electric motor cannot change their torque in abrupt changes.

[0023] Therefore, a setpoint speed precalculation is proposed that limits not only the speed gradient but also the derivative of the speed gradient (speed curvature). To this end, the precalculation must continuously monitor the actual target speed of the internal combustion engine or electric machine and determine the setpoint speed for the next step based on the maximum permissible speed gradient and the maximum permissible speed curvature.

[0024] The conventional two-stage limitation of the speed gradient and speed curvature leads to overshoot, which should be avoided for speed control purposes. Therefore, it is proposed to extend the two-stage limitation of the speed gradient and speed curvature with a braking function. To this end, the exact permissible speed gradient is continuously determined so that the currently permissible speed curvature (corresponding to the torque gradient) and, given the currently prevailing rate of change of the target speed, is precisely tangential to the target speed curve. As a result, the speed gradient can be continuously reduced as the target speed is approached, thereby maintaining the permissible torque gradients for the internal combustion engine and the electric motor. This prevents overshoot of the new reference variable (the rated speed for the internal combustion engine and the electric motor), and allows speed control to fully utilize the full dynamics of the drive system.

[0025] Based on the new reference variable and its first and second time derivatives, it is now possible to construct a speed controller with a very precise pilot control, which already operates the controlled system in a well-controlled manner without controller intervention. This characteristic allows operation with relatively long dead times in the control circuit and, for example, allows the internal combustion engine and electric motor to be controlled via a vehicle bus such as CAN or FlexRay. The original speed controller "only" corrects the error between the controlled system and the pilot control and can therefore adjust the speed difference required for the interlocking shifting element.

[0026] The DHT (Dedicated Hybrid Transmission) is the most common hybrid transmission currently used in vehicles with an internal combustion engine and at least one electric motor. The electric motor (in this case, the first electric motor of the transmission) is part of the transmission and can be connected to various transmission shafts.

[0027] The use of positive-locking shifting elements for gear formation and force transmission in DHT drives offers the potential for maximum efficiency in force transmission and minimal power requirements due to demand-driven actuation. However, positive-locking shifting elements also present challenges. In conventional manual transmissions or similar automated systems, force transmission is completely interrupted before the positive-locking shifting element is actuated. This load-free nature allows the positive-locking shifting element to be opened or closed without affecting the drive and with relatively little effort. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be described below with the aid of the accompanying drawings.

[0029] Figure 1State 1 shows the entire shifting process when shifting from a first fixed gear to a second fixed gear by means of the automatic transmission according to the invention;

[0030] Figure 2 Schematic illustration of the important components of a motor vehicle or a transmission according to the invention and their states in state 1 of the entire shifting process;

[0031] Figure 3 State 2 shows the entire shifting process when shifting from a first fixed gear to a second fixed gear by means of the automatic transmission according to the invention;

[0032] Figure 4 Schematic illustration of the important components of a motor vehicle or a transmission according to the invention and their states in state 2 of the entire shifting process;

[0033] Figure 5 State 3 shows the entire shifting process when shifting from a first fixed gear to a second fixed gear by means of the automatic transmission according to the invention;

[0034] Figure 6 Schematic illustration of the important components of a motor vehicle or a transmission according to the invention and their states in state 3 of the entire shifting process;

[0035] Figure 7 State 4 shows the entire shifting process when shifting from a first fixed gear to a second fixed gear by means of the automatic transmission according to the invention;

[0036] Figure 8 Schematic illustration of the important components of a motor vehicle or a transmission according to the invention and their states in state 4 of the entire shifting process;

[0037] Figure 9 State 5 shows the entire shifting process when shifting from a first fixed gear to a second fixed gear by means of the automatic transmission according to the invention;

[0038] Figure 10 Schematic representation of the important components of the motor vehicle or the transmission according to the invention and their states in state 5 of the entire shifting process;

[0039] Figure 11 States 6 and 7 show the entire shifting process when shifting from a first fixed gear to a second fixed gear by means of the automatic transmission according to the invention;

[0040] Figure 12 Schematic illustration of the important components of a motor vehicle or a transmission according to the invention and their states in states 6 and 7 of the entire shifting process;

[0041] Figure 13The important intermediate step according to the invention between states 3 and 5 is shown, namely state 4 of the entire shifting process when shifting from a first fixed gear to a second fixed gear by means of the automatic transmission according to the invention (see also Figure 7 and 8 ) a special method technical design solution;

[0042] Figure 14 Schematically showing the Figure 13 The important speed change curve regulated by the important speed regulation module (DRM) of the present invention; and

[0043] Figure 15 Schematically shows the Figure 13 An embodiment of the rotational speed regulation module (DRM) important for the present invention. DETAILED DESCRIPTION

[0044] Figure 1 The initial state when the first gear (fixed gear G1) is engaged before a shift command is given is shown, ie, state 1. Subsequently, a shift command is issued in the electronic control unit SG via a corresponding input signal.

[0045] Figure 2 The most important components of the invention are shown, which are also applicable to Figure 4 、 6 , 8, 10 and 12:

[0046] exist Figure 2 Schematically depicts a hybrid vehicle having an automatic transmission, an internal combustion engine VM, a first electric machine EMA, a second electric machine EMB, a high-voltage storage device HVS, and an electronic control unit SG.

[0047] The automatic transmission comprises an epicyclic gear train UG in the form of a power-split planetary gear mechanism, a transmission mechanism comprising two electric machines EMA and EMB, a first shift element K1 for engaging a first fixed transmission ratio stage G1 (hereinafter also referred to as fixed gear stage G1), and a second shift element B2 for engaging a second fixed transmission ratio stage G2.

[0048] The number of two transmission ratio steps is used here merely for better illustration; in practice a greater number of transmission ratio steps can also be used.

[0049] The automatic transmission further comprises two transmission shafts, namely an input shaft in the form of a drive shaft, via which the automatic transmission is coupled to the internal combustion engine VM in a torque-transmitting manner, and an output shaft in the form of a driven shaft, via which the automatic transmission is coupled to the wheels R of the motor vehicle in a torque-transmitting manner.

[0050] An automatic transmission may also have three or more fixed transmission ratios, in which case it may also have a correspondingly greater number of shift elements that are provided for engaging the other transmission ratios. It is also possible to provide a single shift element for multiple transmission ratios and / or a combination of multiple shift elements for one transmission ratio.

[0051] The planetary gear train UG has a planet carrier 1, a ring gear 2, and a sun gear 3. The epicyclic gear train UG is torque-transmittingly coupled to both the input shaft and the output shaft. Furthermore, the epicyclic gear train UG includes a shaft via which the epicyclic gear train can be torque-transmittingly coupled to the input shaft by means of a first shifting element K1, which forms a clutch, and to a second shifting element B2, which forms a brake. This shaft has a speed-regulating effect on the internal combustion engine VM. In an alternative embodiment, the shifting elements K1 and B2 can be configured for any torque-transmitting function.

[0052] The shifting elements K1 and B2 are each designed as claw clutches. That is, they are form-locking shifting elements and require only a low pressure to hold them in the closed position. In an alternative embodiment, the shifting elements K1 and B2 can be any other suitable shifting elements, such as non-positive shifting elements.

[0053] By operating the first electric machine EMA as a generator and the second electric machine EMB as a motor, a transmission function for adjusting the transmission ratio is provided. Thus, kinetic energy and electrical energy can be converted into each other and the speeds of the two electric machines EMA, EMB can be decoupled from each other.

[0054] The automatic transmission switches from the first gear ratio stage (fixed gear) G1 to the second gear ratio stage (fixed gear) G2 according to the Figure 3 、 5 , 7, 9, 11 and 13 shown in the shift process is carried out.

[0055] according to Figure 1 and 2 , the first fixed transmission ratio G1 is engaged, i.e., the first shift element K1 is closed and the second shift element B2 is open. Furthermore, the transmission is decoupled; that is, the electric machine is not torque-transmittingly coupled to either the input shaft or the output shaft. All speeds nG1 are the same. The first electric machine EMA can be operated as a generator to charge the high-voltage storage device HVS.

[0056] To switch to the second fixed transmission ratio G2, now according to Figure 3 The shift element K1 of the current (old) fixed gear G1 is unloaded.

[0057] like Figure 4As can be seen, the transmission is torque-transmittingly coupled to the output shaft and, via this shaft, to the epicyclic gear train UG. In other words, the second electric machine EMB is connected to the output, or the ring gear 2, or the wheels R, and is operated as a motor and supplied with power from the high-voltage storage device HVS. The internal combustion engine VM can be shut down or can be shut down.

[0058] The first shift element K1 ( K1 is shown with a dashed line) is now relieved of load by means of the transmission via the output shaft by torque superposition.

[0059] At this point the core of the invention begins, which will again be referred to Figure 13 and 14 Provide explanation.

[0060] According to Figure 5 State 3 is shown activated in FIG, and then the switching element K1 is disconnected, as shown in FIG. Figure 6 The open K1 is shown in the figure.

[0061] Then according to Figure 7 State 4, i.e. preferably electrical and continuous transmission ratio adjustment in the power split transmission ratio stage (E-CVT). Figure 8 is shown in FIG by the speed shift at the sun gear 3. Thus, after the first shift element K1 is engaged, the transmission ratio of the second transmission ratio stage (fixed gear) G2 is set by continuous transmission ratio adjustment of the transmission mechanism or electric machine EMA. Brake B2 is still engaged at this point.

[0062] This means that a three-shaft operation occurs, whereby the speed difference at the second shift element B2 is reduced.

[0063] Figure 9 State 5 is shown, in which the shift element B2 is engaged for a new fixed gear G2 .

[0064] Here, in Figure 10 As can be seen from FIG, once the speed difference drops to zero or below a certain limit value, the second switching element B2 is closed. As a result, the second switching element B2 takes over the load from the transmission mechanism and the transmission mechanism can be decoupled (see Figure 10 , motor EMB shown by dashed lines). Brake B2 is not yet loaded (B2 shown by dashed lines).

[0065] exist Figure 11 State 6 and the directly connected state 7 are reached or state 1 is reached again, in which a new switching element B2 can be loaded (in Figure 12 B2 is completely closed in the middle).

[0066] by Figure 12 The gear shifting process is completed (G1=>G2).

[0067] The entire shifting process starting from the current fixed gear (here G1) with the intermediate states according to the invention can be summarized as follows:

[0068] - Unload the old switching element K1 by driving the machine (state 2).

[0069] - Open the old shift element K1 (state 3) (switch to E-CVT mode).

[0070] By activating the speed control module DRM according to the invention, a speed adaptation for transmission ratio adjustment (nG1 => nG2) is carried out in the transmission via the E-CVT mode (state 4).

[0071] - Engage the new switching element (B2) (state 5).

[0072] - Load the new switching element (B2) (state 6).

[0073] - "Separate" motors EMA and EMB (state 7 = state 1) => new fixed gear G2.

[0074] Figure 13 “State 4 ” according to the invention is shown with the rotational speed control module DRM.

[0075] Figure 14 Three important curves of the speed n are shown for an exemplary upshift (negative target speed jump x_Ziel at time t1) with acceleration (increased target speed x_Ziel before and after t1). The following curves show:

[0076] - Solid line: target speed x_Ziel

[0077] - Dashed line: Rated speed y

[0078] -Dotted line: actual speed y_ist

[0079] To control the speed n, the time range T between times T1 and T4 is considered. At time t1, the speed change phase of the upshift begins, and at time t4, the upshift ends. At time t2, the speed gradient is observed. At time t3, the speed curvature is observed. Between the individual times, a first partial observation period A occurs between t1 and t2, a second partial observation period B occurs between t2 and t3, and a third partial observation period C occurs between t3 and t4.

[0080] In order to determine the setpoint speed y from the target speed x_Ziel and to calculate other required variables or parameters, the Figure 15 The function of the rotational speed control module DRM according to the invention is shown in FIG.

[0081] This applies here:

[0082] x_Ziel=target speed

[0083] Δt = sampling time / step size

[0084] dy_limits = maximum allowed speed gradient (positive and negative)

[0085] dy 2 _limits = Maximum allowed speed curvature (positive and negative)

[0086] dy_br_limits = Maximum permissible braking speed gradient (positive and negative)

[0087] dx / dt = the derivative of the signal with respect to time (gradient calculation)

[0088] 1 / z = signal feedback (value at the previous time step)

[0089] y = rated speed n

[0090] Δy = gradient of rated speed (change in y within one time step Δt)

[0091] ΔΔy = curvature of rated speed (change in Δy within one time step Δt)

[0092] y_ist = actual speed n

[0093] At time t1, the target speed x_Ziel changes abruptly due to the change in the transmission ratio of the newly engaged fixed gear G2 relative to the old fixed gear G1. During such a shift, the speed controller typically achieves a speed change of at least 300 rpm up to 2500 rpm or more. To reduce the variance in the operating point of the speed controller, according to the present invention, a braking function fA with first-order gradient limitation in partial observation time period B, second-order gradient limitation in partial observation time period A, and gradient limitation in partial observation time period C generates a signal that is continuous over time range T, namely the target speed y.

[0094] Thus, for example, a speed gradient of the setpoint speed y of the internal combustion engine VM, which can be converted into a required total change in the internal combustion engine torque based on the effective moment of inertia and vice versa, is pre-limited within the operating range of the internal combustion engine (dy_limits).

[0095] Maximum permissible curvature dy at rated speed y of internal combustion engine VM 2_limit can be converted into the required torque gradient of the internal combustion engine VM, and vice versa, similar to the calculation of the speed gradient of the setpoint speed y. Therefore, the time curvature ΔΔy of the speed n achievable by the internal combustion engine VM can also be precalculated and incorporated into the curve of the setpoint speed y.

[0096] The actual speed y_ist of the internal combustion engine VM is an exemplary curve which can be obtained due to a suitable regulator in conjunction with a pilot control via the setpoint speed y and its time derivative.

[0097] The braking function fA is calculated as a function of the curvature dy with respect to the maximum permissible rotational speed. 2 The permissible change in the setpoint speed dy_br_limit for the current step size is determined using information about dy_br_limit, the current step size, the setpoint speed of the previous calculation step, and the current gradient of the target speed.

[0098] In other words, the first-order gradient limitation in the partial observation time period B is designed so that the maximum adjustable torque of the drive motor VM and EMA and / or EMB is not exceeded; that is, for example: y' = dy / dt = MIN ((M_VM, M_EMA) / J) (MIN = minimum torque, J = moment of inertia). The second-order gradient limitation in the partial observation time period A is designed so that the maximum adjustable torque gradient of the drive motor VM and EMA and / or EMB is not exceeded; that is, for example: y'' = (MIN_VM / dt, dM_EMA / dt) / J. The time range T is determined by the braking function fA.

[0099] The following relationship applies to the braking function fA:

[0100]

[0101] In this case, the currently desired braking duration (t−t4) is determined in the square root term as a function of the difference between the target speed and the nominal speed and the achievable speed curvature.

[0102] According to the braking duration and the maximum permissible speed curvature dy 2 _limit in turn yields the currently still permissible speed gradient from the setpoint speed.

[0103] The overall function shown places the braking function fA directly after the first gradient limitation and the second gradient limitation in third place. This arrangement has the advantage that the setpoint speed y always complies with the required limits for the speed gradient and speed curvature.

[0104] In a variant of the overall function, the braking function can be set in the third position to limit the gradient of the setpoint speed. However, this variant carries the risk that the limit values ​​of the setpoint speed in terms of gradient and curvature cannot be adhered to in all cases.

[0105] Depending on the height of the speed jump of x_Ziel, it may result in partial observation time period B having to be skipped, ie the maximum speed gradient is not reached and a jump must be made directly from partial observation time period A to partial observation time period C.

Claims

1. A motor vehicle having at least two drive motors (VM, EMA, EMB), wherein: At least one drive motor is an electric motor (EMA), the motor vehicle has a high voltage storage device (HVS), an automatic transmission having at least one fixed transmission ratio step (G1) and at least one power split transmission ratio step (E-CVT) for adjusting the transmission ratio starting from the at least one fixed transmission ratio step (G1), and an electronic control unit (SG), the electronic control unit including a speed control module (DRM) which can be activated during a transmission ratio change and is designed to precalculate a setpoint speed (y) by which both a speed gradient (Δy) and a speed curvature (ΔΔy) can be limited, wherein a target speed (x_Ziel) of the at least one drive motor (VM, EMA, EMB) is continuously compared with a maximum permissible speed gradient (dy_limits) and a maximum permissible speed curvature (dy_limits). 2 _limits) for comparison.

2. The motor vehicle according to claim 1, wherein: The limitation of the speed gradient (Δy) and the speed curvature (ΔΔy) is extended by a braking function (fA), wherein exactly how much of the speed gradient is still permitted (dy_br_limits) is continuously determined so that the setpoint speed (y) is exactly tangential to the target speed curve (x) while observing the currently permitted speed curvature and the currently existing rate of change (dx / dt) of the target speed (x_Ziel).

3. The motor vehicle according to claim 2, characterized in that In the speed control module (DRM), the gradient limitation (C) of the braking function (fA) is connected directly after the first-order gradient limitation (B), and the second-order gradient limitation (A) is connected after the gradient limitation (C).

4. The motor vehicle according to claim 2, characterized in that In the speed control module (DRM), the gradient limitation (C) of the braking function (fA) is connected directly after the second-order gradient limitation (A), and the second-order gradient limitation (A) is connected after the first-order gradient limitation (B).

5. An automatic transmission for a motor vehicle according to any one of claims 1 to 4, comprising an epicyclic gear train (UG), at least one shifting element (K1 and / or B2), at least one electric motor (EMA) as a drive motor, and an actuator controllable by an electronic control unit (SG), wherein: The electronic control unit (SG) comprises a speed regulation module (DRM) which can be activated during a transmission ratio change and is designed to precalculate a setpoint speed (y) by which both a speed gradient (Δy) and a speed curvature (ΔΔy) can be limited, wherein a target speed (x_Ziel) of at least one drive motor (VM, EMA, EMB) is continuously compared with a maximum permissible speed gradient (dy_limits) and a maximum permissible speed curvature (dy 2 _limits) for comparison.

6. An electronic control unit (SG) for a motor vehicle according to any one of claims 1 to 4 or an automatic transmission according to claim 5, the electronic control unit comprising a speed regulation module (DRM) for controlling the at least two drive motors (VM, EMA, EMB) and the shifting elements (K1, B2) such that a setpoint speed (y) is precalculated, by which both a speed gradient (Δy) and a speed curvature (ΔΔy) can be limited, wherein: Continuously compares the target speed (x_Ziel) of at least one drive motor (VM, EMA, EMB) with the maximum permissible speed gradient (dy_limits) and the maximum permissible speed curvature (dy 2 _limits) for comparison.

7. A method for shifting an automatic transmission in a motor vehicle according to any one of claims 1 to 4, wherein: After a shift command is given, a target speed (y) is precalculated by means of an electronic control unit (SG), by which both the speed gradient (Δy) and the speed curvature (ΔΔy) can be limited, wherein the target speed (x_Ziel) of the at least one drive motor (VM, EMA, EMB) is continuously compared with the maximum permissible speed gradient (dy_limits) and the maximum permissible speed curvature (dy 2 _limits) for comparison.

Images